plcont.3plplot man page

plcont — Contour plot


plcont(f, nx, ny, kx, lx, ky, ly, clevel, nlevel, pltr, pltr_data)


Draws a contour plot of the data in f[nx][ny], using the nlevel contour levels specified by clevel. Only the region of the array from kx to lx and from ky to ly is plotted out.  A transformation routine pointed to by pltr with a pointer pltr_data for additional data required by the transformation routine is used to map indices within the array to the world coordinates.  See the following discussion of the arguments and the PLplot documentation for more information.

Redacted form: [PLEASE UPDATE! ONLY PERL INFO IS LIKELY CORRECT!] F95: plcont(f, kx, lx, ky, ly, clevel, tr?) or plcont(f, kx, lx, ky, ly, clevel, xgrid, ygrid) Java: pls.cont(f, kx, lx, ky, ly, clevel, xgrid, ygrid) Perl/PDL: plcont(f, kx, lx, ky, ly, clevel, pltr, pltr_data) Python: plcont2(f, kx, lx, ky, ly, clevel)

This function is used in examples 9,14,16,22.


f (const PLFLT * const *, input)

Pointer to a vectored two-dimensional array containing data to be contoured.

nx, ny (PLINT, input)

Physical dimensions of array f.

kx, lx (PLINT, input)

Range of x indices to consider.

ky, ly (PLINT, input)

Range of y indices to consider.

clevel (const PLFLT *, input)

Pointer to array specifying levels at which to draw contours.

nlevel (PLINT, input)

Number of contour levels to draw.

pltr (void (*) (PLFLT, PLFLT, PLFLT *, PLFLT *, PLPointer) , input)

Pointer to function that defines transformation between indices in array f and the world coordinates (C only).  Transformation functions are provided in the PLplot library: pltr0(3plplot) for identity mapping, and pltr1(3plplot) and pltr2(3plplot) for arbitrary mappings respectively defined by one- and two-dimensional arrays.  In addition, user-supplied routines for the transformation can be used as well.  Examples of all of these approaches are given in the PLplot documentation. The transformation function should have the form given by any of pltr0(3plplot), pltr1(3plplot), or pltr2(3plplot). Note that unlike plshades(3plplot) and similar PLplot functions which have a pltr argument, plcont requires that a transformation function be provided in the C interface.  Leaving  pltr NULL will result in an error.

pltr_data (PLPointer, input)

Extra parameter to help pass information to pltr0(3plplot), pltr1(3plplot), pltr2(3plplot), or whatever routine that is externally supplied.


Many developers (who are credited at have contributed to PLplot over its long history.

See Also

PLplot documentation at


August, 2015 PLplot API